Vodacom - Incorrect Balance on account

For the last couple of months, there has been an extra R3000 on my wife's account, it should only be the R1700, when we query it and ask vodacom where it comes from they can't answer us, we have spoken to multiple consultants and they all promise to sort it out but the amount keeps reflecting. We spoke to a consultant (Lovu not sure how to spell his name) on the 7th of October and he told us he can't see any issue on the account and he will forward it to the accounts department to sort it out. Still hasn't happened.